Potential of municipal wastewater for resource recovery and reuse

There has been significant progress in innovative research and development in wastewater-related resource recovery and reuse with continuously increasing volumes of municipal waste streams. A paradigm shift is underway from a mindset that considers municipal wastewater a waste to a proactive interest in recovering water, nutrients, and energy from this valuable resource generated by domestic, industrial, and commercial sectors. Current estimates based on the data simulation suggest annual wastewater production across the world at 411km3 (411 billion m3 or 411 trillion L). Such wastewater production is expected to be 470km3 in 2030 and 574km3 in 2050, that is, 14% and 40% increase over 2020, respectively. Wastewater carries significant amounts of macronutrients. Collectively, 28.0 Tg (28.0×1012 g or 28.0 million metric tons) of nitrogen (18.0 Tg), phosphorus (3.2 Tg), and potassium (6.8 Tg) are present in municipal wastewater produced globally. The energy present in wastewater is enough to provide electricity to 171 million households. Although the full potential of resource recovery from wastewater is yet to be achieved, there is a steady increase in resource recovery efficient systems every year. Resource recovery innovations are being effectively implemented and refined in high-income and upper-middle-income countries. Such innovative research and development efforts are lacking in low- and middle-income countries, which need to implement pertinent innovations as wastewater treatment in these countries continues to be low.